In the production of III-V semiconductor components, masking steps are usually used to structure the surface of a sample. The surface of the sample is partially covered with a mask, for instance a mask made of SiO2 as an amorphous material. The sample material is then removed in the region which is not covered by the mask by an etching step (a dry or wet chemical process).
The term xe2x80x9csamplexe2x80x9d refers to any material which is structured in the course of manufacturing semiconductor components.
The disadvantage of this procedure is that, in order to remove the SiO2 mask from the surface, the sample must be removed from the epitaxy apparatus, thereby exposing the sample to airborne contaminants and oxygen. The contamination is particularly bad in structures containing aluminum, because this comprises a high bonding affinity to oxygen. Since such structures are highly significant to semiconductor laser production, the contamination is particularly problematic.
The invention sets forth a method by which it is possible to easily remove the mask from semiconductor material and apply additional layers in-situ in the manufacture of III-V semiconductor components. The method produces a structure for III-V semiconductor components in which a mask is applied to a sample in a masking step, characterized in that at least one mask material is a monocrystalline III-V semiconductor material.
Using a monocrystalline III-V semiconductor material in at least one mask material, it is possible to create a xe2x80x9cself-dissolvingxe2x80x9d mask which is removable from the sample in-situ. The mask is dissolved during etching, which saves a substantial amount of processing time.
It is advantageous if at least one mask material is GaxIn1xe2x88x92yAsyP1xe2x88x92y or AlGaInAs. These materials can be removed in a highly controlled fashion by etching the sample.
It is particularly advantageous when the creation of a structure on and/or in the mask, specifically by lithography, is followed by an etching step with tertiary butyl chloride (TBCl) as the etching agent. This etching agent is appreciably milder than the halogenic hydrogen compounds (e.g. HCl) commonly used in in-situ methods. Moreover, the etch rate of this agent is particularly easy to control.
It is advantageous to select the etch rate in the etching step in dependence upon the composition of the mask material, so that the mask is dissolved during etching. A self-dissolving mask can thus be created, in which the etch rate is advantageously precisely selected such that the mask is gone from the sample at the end of the etching step.
The etching step is expediently performed in-situ in the same device in which the structure has been applied in and/or on the sample.
Advantageously, after the etching step at least one epitaxial layer, particularly a guard layer, is applied to the surface. This is also performed in-situ.
The semiconductor component that emerges upon completion of the method can expediently be utilized in a semiconductor laser.